Cyclonic stripping blade

ABSTRACT

A blade assembly is provided for use in a wire stripping system, where the blade assembly includes a first blade including a first cutting opening therein, the first opening including a first guide surface on one side of the first opening and a first cutting surface on the opposite side of the first opening, and a second blade including a second cutting opening therein, the second opening including a second guide surface on one side of the second opening and a second cutting surface on the opposite side of the second opening. The blades impart a rotation force on the wire to cause the cutting surfaces to make a depth-controlled circumferential cut in the sheath around the entire wire.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority as a continuation of U.S.Non-Provisional application Ser. No. 12/908,204 filed on Oct. 20, 2010,now U.S. Pat. No. 8,739,665, which in turn claims priority from U.S.Provisional Application Ser. No. 61/253,531, filed on Oct. 21, 2009, theentirety of which are each hereby expressly incorporated by referenceherein.

FIELD OF THE INVENTION

The present invention relates to machines utilized in the manufacture ofelectronic devices, and more particularly to machines utilized to stripthe insulating coating from wires used in the construction of theelectronic and electrical devices.

BACKGROUND OF THE INVENTION

In the manufacture of electronic devices, wiring of various types andsizes is required to complete the necessary electrical connection forproper operation of the device. The wires used in this manufacture asformed with a conductive core, normally formed from a type of metal,surrounded by an insulting material sheath. The insulating materialsheath is formed to closely conform to the shape of the conductive core,and is formed of a material that is both electrically insulating, anddurable to provide effective insulation to the wiring.

However, because the wiring formed in this manner is utilized for makingelectrical connections in various types of devices, during themanufacture of the devices it is necessary to expose the ends of theconductive core of the wiring in order to facilitate the construction ofthe device. Therefore, when wiring having an insulating material sheathis utilized, portions of the sheath usually must be removed.

In prior art devices developed for removing portions of the insulatingsheath, blades are utilized to cut through the sheath material such thatit can be stripped off of the conductive core. These blades weredesigned to utilize one of two cutting methods. In the first pushcutting method, a pair of opposed blades are each formed with agenerally flat cutting surface having a central notch formed therein.The notches are disposed in alignment with one another and are formed tohave a radius approximately equal to the radius of the conductive coreof the wiring being stripped. To remove the conductive sheath from thewiring, the wiring is positioned between the blades in alignment withthe notches and the blades are moved towards each other. The cuttingedges of the blades engage the insulating material sheath on both sidesof the wiring and sever the portion to be removed from the remainder ofthe sheath. While the sheath material is being severed the conductivecore is located within the notches to limit the contact of the cuttingsurfaces with the core.

One significant drawback with regard to this cutting method is that,while it is possible to control the depth of the cut through the sheathat the center of each notch in the cutting swine, the cutting surface oneach end of the notch can insufficiently sever the sheath, as the sheathis squeezed between the opposed blades. Further, if the blades arecompressed further to sever the squeezed sections of the sheath, thiscan nick the conductive core, thereby reducing the current carryingcapacity of the core.

As an alternative to the push cutting blades and method, a secondcutting and stripping method involves the use of V-shaped blades. Inthis method, the blades each have a V-shaped opening formed in thecutting surface of the blade, with the cutting edge running completelyalong the periphery of the opening. The opening terminates in a roundedend that corresponds generally in shape to the circumference of thewiring to be cut and stripped using the blades.

In operation, the wiring is positioned between the blades, and theblades are subsequently moved towards one another. The V-shape of theopenings in the blades urges the wiring towards the rounded ends of eachblade until the wiring is captured in the rounded ends. During themovement of the wiring towards the capture position and at this point,the cutting edges on the sides and rounded ends of the openings engageand cut into the insulating material sheath. As a result of the shape ofthe rounded ends of the openings, any contact of the cutting edges withthe conductive core of the wiring is limited, to minimize any nicking ofthe conductive core by the cutting edges of the blades.

However, while the shape of the rounded ends of the openings attempts tominimize contact of the cutting edges with the conductive core of thewiring, similarly to the issues with the push cutting blades and method,the V-shape blades and method cannot effectively control the depth ofthe cut into the sheath, such nicks in the conductive core occur.

Therefore, it is desirable to develop a cutting blade and method forutilizing the blade that provides a controlled-depth cut into theinsulating material sheath on a coated wire to minimize nicking orotherwise damaging the conductive core of the wiring.

SUMMARY OF THE INVENTION

Thus, according to one aspect of the present disclosure, a strippingblade is designed with specific geometry that features a single,compound cutting edge along one side of the stripping form with anopposing guiding surface along the adjacent edge that also mechanicallydefines the depth of the cut or insulation penetration. The bilateralsymmetry of the guiding surface also creates a “cyclonic” or rotationalforce on the wiring that creates a complete 360° circumferential cutinto the insulating material as the pair of stripping blades moverelative to each other. The circumferential cutting minimizes the amountof insulating material that is squeezed and/or torn during the strippingor removal process and thus greatly reduces the amount of force requiredto perform the operation.

According to another aspect of the present disclosure, the strippingblade geometry features a unique stripping form geometry with bilateralsymmetry and internal guiding. Further, the stripping blade includes amechanically defined depth of insulation penetration and a cyclonicstripping action that slices, rather than pushes or compresses, into theinsulating material, creating a superior cut.

Numerous other aspects, features and advantages of the presentdisclosure will be made apparent from the following detailed descriptiontaken together with the drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode currently contemplated forpracticing the present invention.

In the drawings:

FIGS. 1( a)-1(d) are isometric views of a the operation of the strippingblades to strip a portion of an insulating material sheath from aconductive core;

FIGS. 2( a)-2(d) are front plan views of the operation of the snippingblades corresponding to FIGS. 1( a)-1(d);

FIG. 3 is a front plan view of a first stripping blade constructedaccording to the present disclosure;

FIG. 4 is first isometric view of the blade of FIG. 3;

FIG. 5 is a second isometric view of the blade of FIG. 3;

FIG. 6 is a side plan view of the blade of FIG. 3;

FIG. 7 is a partially broken away, cross-sectional along line 7-7 ofFIG. 3;

FIG. 8 is a front plan view of a complementary, second stripping bladeconstructed according to the present disclosure;

FIG. 9 is first isometric view of the blade of FIG. 8;

FIG. 10 is a second isometric view of the blade of FIG. 8;

FIG. 11 is a side plan view of the blade of FIG. 8;

FIG. 12 is a partially broken away, cross-sectional along line 12-12 ofFIG. 8; and

FIG. 13 is partially broken away, front plan view of the engagement ofthe first and second blades with a wire.

DETAILED DESCRIPTION OF THE INVENTION

With reference now to the drawing figures in which like referencenumerals designate like parts throughout the disclosure, a pair ofstripping blades forming a blade assembly 1000 and constructed inaccordance with the present disclosure is illustrated generally at 10and 12 in FIGS. 1( a)-1(d). FIGS. 1( a)-1(d) illustrate the movement ofthe pair of stripping blades 10, 12 to remove the insulation from aportion of an insulated electrical cable 14. As the stripping blades 10,12 move relative to each other, as illustrated by arrows 16, theconfiguration of the stripping blades 10, 12 slices through theinsulation 17 disposed around the conductive metal wire core 19 andremoves an end section 20 of the insulation 17. As shown in FIGS. 1( b)and 1(c), the blades 10, 12 sever only the insulation 17 surrounding themetallic wire core 19 within the cable 14 such that when the cable 14 ismoved in the direction shown by arrow 18 in FIG. 1( d), the end sectionor slug 20 is stripped off of the metal wire core 19. The exposed end 21of the wire core 19 can then make electrical contact with othercomponents or connectors. The present disclosure is directed to thespecific configuration of the pair of stripping blades 10, 12 shown inFIGS. 1( a)-1(d).

Referring now to FIGS. 2( a)-2(d) and 3, the stripping blade 12 isformed with a body 23 of a suitable material, such as a metal, andincludes a mounting aperture 100 that receives a fastener (not shown)therein to secure the blade 12 to a device for moving the blade 12during a cutting operation, and a smooth guide surface 22 and a cuttingsurface 24 that combine to define opposed sides of a V-shaped opening 26spaced from the mounting aperture 100. The opening 26 in one embodimentis shaped with an angle of approximately 30°, though other angles forthe opening 26 are contemplated as being within the scope of thedisclosure, and terminates at a semicircular cutting edge 28, as bestshown in FIG. 7. Positioned below the cutting edge 28 is a slopinglead-in surface 30. As illustrated in FIG. 6, the sloping lead-insurface 30 is positioned at an angle of approximately 30° relative tothe generally planar face surface 32 of the cutting blade 12. Thelead-in surface 30 provides edge strength to the cutting edge 28 toenable the cutting edge 28 to more easily sever the insulation 17 of thewiring or cable 14. Depending upon the particular wire wiring or cable14 being cut, and the corresponding insulation 17 and/or wire core 19therein, the lead-in surface 30 can be varied in shape to have an anglethat provides the best edge strength to the cutting edge 28. The angleof the surface 30 can be varied from 15° to 45° relative to thegenerally planar face surface 32 of the cutting blade 12, but for themajority of wires 14 to be cut, and angle of between 20° to 30° relativeto the generally planar face surface 32 of the cutting blade 12 issufficient.

The stripping blade 10, as shown in FIGS. 8-12, is formed similarly andcomplementary to, and optionally as a mirror image of, the blade 12, andincludes a planar face surface 34 and a similar semicircular cuttingedge radius 36. The stripping blade 10 includes a sloping lead-insurface 38 that is also positioned at the same or a similar angle as thesurface 30 on the blade 12, as shown in FIG. 11.

The stripping blade 10 shown in FIG. 8 also includes a cutting surface42 and an opposite guide surface 40 that define the V-shaped opening 48.As can be understood in FIGS. 3 and 8, the cutting surface 24 formed onthe stripping blade 12 is located on an opposite side from the cuttingsurface 42 contained on the stripping blade 10. Further, the cuttingedge radius 28 shown in FIG. 7 and the cutting edge radius 36 shown inFIG. 12 correspond to each other and are sized dependent upon the typeof cable or wire 14, and the corresponding thickness of the insulatingmaterial sheath 17 and conductive core 19 utilized with the strippingblades 10, 12.

Also, as best shown in FIGS. 6 and 11, the body 23 of each of the blades10 and 12 is formed with a thicker portion 200, in which the mountingaperture 100 is located, and a thinner portion 202, in which theV-shaped openings 26 and 48 are disposed. The presence of the mountingaperture 100 in the thicker portion 200 provides the blades 10 and 12with increased strength and rigidity around the mounting aperture 100.This enables the blades 10 and 12 to be securely mounted to a suitabledevice and withstand the stress applied to the blades 10 and 12 duringoperation of the device.

Further, the V-shaped openings 26 and 48 are disposed in the thinnerportions 202 of each blade 10 and 12. The thinner portions 202 areconfigured to have a thickness approximately equal to one half of thethickness of the thicker portions 200, such that the blades 10 and 12can be mounted to the device in a configuration where the thinnerportions 202 of each blade 10 and 12 are aligned with at least a part ofthe thicker portion 200 of the opposing blade 10,12, to minimize thesize of the blade pair in the mounted configuration on the device.Additionally, in this position, the thinner portions 202 can be disposedclosely to one another, and optionally in sliding contact with oneanother, to facilitate the severing of the insulation slug 20 from thewire 14 by the openings 26 and 48 on each blade 10 and 12.

Referring back to FIGS. 1( a)-1(d) and 2(a)-2(d), when the strippingblades 10, 12 are moved relative to each other to strip a section orslug 20 of insulation 17 from the electrical cable 14, the electricalcable 14 is initially positioned between the blades 10 and 12 and heldstationary as it contacts either the guide surface 22 of the strippingblade 12, or the guide surface 40 of the stripping blade 10, dependingupon the orientation of the blades 10 and 12. As illustrated in theconfiguration shown in FIGS. 1( a) and 2(a), the guide surface 22 on thestripping blade 12 interacts with the cutting surface 42 of thestripping blade 10, while the cutting surface 24 of the stripping blade12 interacts with the guide surface 40 of the stripping blade 10.

As can be understood in FIGS. 1( b), 1(c), 2(b) and 2(c), as thestripping blades 10, 12 move towards one another in the direction shownby arrows 16, the cutting surface 42 contacts the cable 14, which causesthe cable 14 to rotate in the direction shown by arrow 44.Alternatively, by varying the position of the blades 10,12 and/or thewire 14, it is possible to cause the wire 14 to rotate in acounterclockwise direction, if desired. Further movement of thestripping blades 10 and 12 relative to each other causes the cable 14 tocontinue to rotate in the direction shown by arrow 44, which aids inurging the cutting surface 42 into the insulation 17 on the wire 14 asthe wire 14 is rotating to create a depth-controlled circumferential cutthrough the exposed surface 17′ of the insulation 17 on the electricalcable 14. The depth-control function of the blades 10 and 12 is providedby the engagement of the wire 14 by the guide surface 22, which preventsthe cutting surface 42 from cutting too deeply into the sheathinsulation material 17 as the wire 14 is rolled along the cuttingsurface 42.

The movement of the blades 10 and 12 and consequent rotation of thecable 14 continues until the blades 10 and 12 reach their fully engagedposition shown in FIGS. 1( d) and 2(d). When the stripping blades 10, 12are in the fully engaged position shown in FIGS. 1( d) and 2(d), thecutting edge radius 28 of the stripping blade 12 and the cutting edgeradius 36 of stripping blade 10 combine to define a circular opening 50having a diameter slightly larger than the diameter of the conductivecore 19 of the wire 14. As illustrated in FIG. 13, the cutting edgeradiuses 28, 36 sever the insulation 17 such that the slug 20 can bestripped from the insulation 17 remaining on the wire 14 when the wire14 is moved in the direction shown by arrow 18 in FIG. 1( d).

To facilitate the removal of the slug 20, the blades 10 and 12 each havea stop 300 located within the V-shaped opening 26,48 at the intersectionof the guide surface 22,40 with the cutting edge 28,36. The stop 300includes a projection 302 that extends into the Opening 26,48 past thecutting edge 28,36 and is spaced from a centerline of the cutting edge28,36 a distance slightly less than the thickness of the Wire 14. Inthis position, when the cutting surfaces 24 and 42 and cutting edges 28and 36 have completed forming the circumferential cut in the insulation17 to form the plug 20, the projections 302 on the stops 300 arepositioned within the cut to provide a stop against movement of the plug20 with the remainder of the wire 14 when the wire 14 is moved in thedirection shown in FIG. 1( d). In addition, the stop 300 provides alocating function within the opening 50 defined by the cutting edges28,36 to properly locate the wire 14 between the blades 10 and 12 andcomplete the circumferential cut in the insulation 17.

After the wire 14 is withdrawn from the blade assembly 1000, the blades10 and 12 can be drawn away from one another to the position in FIGS. 1(a) and 2(a), where an additional length of wire 14 can be positionedbetween the blades 10 and 12 to sever the sheath 17 in manner previouslydescribed.

As can be understood in the above description and specifically withrespect to FIGS. 3 and 8, each of the stripping blades 10, 12 include aguide surface 22,40 opposite a cutting surface 24,42, that eachterminate at a cutting edge 28,36. Unlike prior stripping blade designsthat include a cutting edge on each side of the opening that receivesthe wire to be cut, the movement of the stripping blades 10,12 relativeto each other, and the consequent engagement of the wire 14 with theguide surfaces 22,40 and cutting surfaces 24,42 creates a “cyclonic” orrotational force that rotates the wiring 14 as it is cut by the surfaces24,42 and edges 28,36 to form a circumferential cut into the insulatingmaterial 17, which can be a complete 360° cut into the insulation 17.The circumferential cut into the insulation material 17 minimizes theamount of insulating material 17 that remains uncut, both on the exposedsurface 17′ of the insulation 17 and between the exposed surface 17′ andthe core 19. In one embodiment, the blades 10,12 are configured to forma circumferential cut through all of the exposed surface 17′ of theinsulation 17, while leaving a predetermined amount of insulation 17between the exposed surface 17′ and the core 19 uncut. In anotherembodiment, the blades 10,12 can be configured to circumferentially cutthrough the entire insulation 17 down to a desired distance from thecore 19, or all the way through the insulation 17 to the core 19.However, in all configurations of the blades 10,12 and depth of theresulting circumferential cut, the circumferential cut minimizes theuncut insulation 17 on the exposed surface 17′ or within the insulation17 that is necessarily torn during the stripping or removal processshown in FIG. 1( d) when the stops 300 hold the plug 20 in place whilethe remainder of the wire 14 is removed from the blades 10,12. By makingthe cut in this manner, the blades 10,12 enable the wiring 14 to beformed with a clean, exposed end 400 of the core 19 that easily beelectrically engaged with a suitable electric or electronic device.

Various alternatives are contemplated as being within the scope of thefollowing claims particularly pointing out and distinctly claiming thesubject matter regarded as the invention.

What is claimed is:
 1. A method for severing a portion of an insulatingmaterial sheath from a wire, the method comprising the steps of: a)providing a blade assembly including a first blade having a firstcutting opening therein, the first opening including a first flat guidesurface on one side of the first opening and a first cutting surface onthe opposite side of the first opening, and a second blade including asecond cutting opening therein, the opening including a second flatguide surface on one side of the second opening and a second cuttingsurface on the opposite side of the second opening; b) positioning awire including an insulating material sheath thereon between the firstblade and the second blade; and c) engaging the first blade and thesecond blade with the insulating material sheath, wherein the step ofengaging the first blade and the second blade with the insulatingmaterial sheath simultaneously rotates and cuts the sheath.
 2. A methodfor severing a portion of an insulating material sheath from a wire, themethod comprising the steps of: a) providing a blade assembly includinga first blade having a first cutting opening therein, the first openingincluding a first flat guide surface on one side of the first openingand a first cutting surface on the opposite side of the first opening,and a second blade including a second cutting opening therein, theopening including a second flat guide surface on one side of the secondopening and a second cutting surface on the opposite side of the secondopening; b) positioning a wire including an insulating material sheaththereon between the first blade and the second blade; and c) engagingthe first blade and the second blade with the insulating materialsheath, wherein the first cutting opening includes a first cutting edgeconnected to the first cutting surface and the first guiding surface,and the second opening includes a second cutting edge connected to thesecond cutting surface and the second guiding surface, and wherein themethod further comprises the step of engaging the sheath within thefirst and second cutting edges after engaging the sheath with the firstor second cutting surfaces and first or second guiding surfaces tocomplete the cut in the sheath and wherein the first and second cuttingedges each include a stop, and wherein the method further comprises thesteps of: a) engaging the stops with the cut in the sheath; and b)removing a severed portion of the sheath from the wire.